This extension provides syntax highlighting for Apptainer/Singularity definition files.
Syntax highlighting of Singularity definition files on GitHub is also based on this extension.
Currently, only files that have Singularity as the exact file name are recognized.
To recognize other files, e.g., Singularity.* and *.def, a .gitattribute file with additional rules/patterns can be added to GitHub repositories (example).
The interpolation, keyword, string, and variable patterns (Bash) originate from microsoft/vscode.